This procedure requires the use of the GM Seal Installer/Centering tool No. J-34995 or equivalent.

Disconnect the negative battery cable for safety.

Refer to the Crankshaft Pulley, Damper and Oil Seal, Removal and
Installation procedures in this section and remove the damper from the
crankshaft.

If not done already, remove the fan and the pulley.

Remove the alternator and the brackets from the front of the engine.

Remove the lower radiator hose clamp at the water pump.

Remove the timing cover bolts and cover. Check for bolts threaded
from the front of the oil pan to the bottom of the cover. If present,
these must be removed before attempting to loosen the cover.

If the front seal is to be replaced, it can be pried out of the cover with a small prytool.

Using a plastic scraper, clean the gasket mounting surfaces. Then
clean the surface with solvent to remove all traces of oil and grease.

The timing cover can become distorted very easily, so be careful when cleaning the gasket surface.To install:

Apply engine oil to the lips of the new oil seal. Using the GM
Seal Installer/Centering tool No. J-34995 or equivalent, install the
new oil seal into the timing cover; leave the tool installed in the
timing cover.

Fig. 7: If you install a replacement front seal with the cover OFF the engine, BE SURE TO SUPPORT IT to prevent damage

1985-95 Models

The following procedure requires the use of a torsional damperpuller/installer tool such as GM tool no. J-23523-E (1985-92 models),J-39046 (1993-95 models) or an equivalent, and the GM Seal Installertool No. J-35468 or equivalent.

Disconnect the negative battery cable for safety.

Remove the water pump assembly from the engine. For details, please refer to the procedure found earlier in this section.

Remove the crankshaft pulley and damper. For details, please refer to the procedure found earlier in this section.

Either loosen or remove the oil pan, as necessary. For 1985-91models the manufacturer recommends that the oil pan be removed. For1992-95 models the manufacturer recommends that the pan just beloosened. It is possible that this can be done on earlier models aswell, but caution must be taken to prevent front cover and oil pan sealdamage.

For 1995 vehicles, remove the crankshaft position sensor.

Remove the timing cover-to-engine bolts, then carefully removethe cover from the engine. If the oil pan was not removed, be carefulnot to damage the oil pan-to-front cover seal or sealing surfaces.

Using a plastic scraper, clean the gasket mounting surfaces.Using solvent and a rag, clean the oil and grease from the gasketmounting surfaces.

If the front cover seal is to be replaced, it may be pried frontthe front cover using a suitable prytool. Take care not to score anddamage the seal bore, and take even greater care NOT TO distort thecover metal.

Inspect the timing cover for distortion and damage, if necessary, replace it.

To install:

Beginning in 1992, the manufacturer began suggesting you wait untilthe front cover is mounted to the engine before you install thereplacement crankshaft oil seal. This may be to assure the cover isproperly supported. On earlier vehicles, the manufacturer allowed forinstallation with the cover removed or installed, so waiting would beacceptable for all years of the 4.3L engine.

If desired on early-model engines, install a new seal to thecover using a suitable installation driver, such as J-35468 orequivalent. Be sure to support the back of the seal cover area duringinstallation to prevent the cover from becoming distorted or damaged.Lightly coat the lips of the new seal with clean engine oil.

The oil seal is installed with the open end of the seal lips facing toward the inside of the engine.

Position a new front cover gasket to the engine or cover using ahigh-tack gasket cement to hold it in position. If the oil pan was notremoved, lubricate the front of the oil pan seal with clean engine oilto aid in reassembly.

Install the front cover to the engine. If the oil pan is still inplace, take care while engaging the front of the oil pan seal with thebottom of the cover.

Fig. 7: If you install a replacement front seal with the cover OFF the engine, BE SURE TO SUPPORT IT to prevent damage

1985-95 ModelsThe following procedure requires the use of a torsional damper
puller/installer tool such as GM tool no. J-23523-E (1985-92 models),
J-39046 (1993-95 models) or an equivalent, and the GM Seal Installer
tool No. J-35468 or equivalent.

Disconnect the negative battery cable for safety.

Remove the water pump assembly from the engine. For details, please refer to the procedure found earlier in this section.

Remove the crankshaft pulley and damper. For details, please refer to the procedure found earlier in this section.

Either loosen or remove the oil pan, as necessary. For 1985-91
models the manufacturer recommends that the oil pan be removed. For
1992-95 models the manufacturer recommends that the pan just be
loosened. It is possible that this can be done on earlier models as
well, but caution must be taken to prevent front cover and oil pan seal
damage.

For 1995 vehicles, remove the crankshaft position sensor.

Remove the timing cover-to-engine bolts, then carefully remove
the cover from the engine. If the oil pan was not removed, be careful
not to damage the oil pan-to-front cover seal or sealing surfaces.

Using a plastic scraper, clean the gasket mounting surfaces.
Using solvent and a rag, clean the oil and grease from the gasket
mounting surfaces.

If the front cover seal is to be replaced, it may be pried front
the front cover using a suitable prytool. Take care not to score and
damage the seal bore, and take even greater care NOT TO distort the
cover metal.

Inspect the timing cover for distortion and damage, if necessary, replace it.

To install:Beginning in 1992, the manufacturer began suggesting you wait until
the front cover is mounted to the engine before you install the
replacement crankshaft oil seal. This may be to assure the cover is
properly supported. On earlier vehicles, the manufacturer allowed for
installation with the cover removed or installed, so waiting would be
acceptable for all years of the 4.3L engine.

If desired on early-model engines, install a new seal to the
cover using a suitable installation driver, such as J-35468 or
equivalent. Be sure to support the back of the seal cover area during
installation to prevent the cover from becoming distorted or damaged.
Lightly coat the lips of the new seal with clean engine oil.

The oil seal is installed with the open end of the seal lips facing toward the inside of the engine.

Position a new front cover gasket to the engine or cover using a
high-tack gasket cement to hold it in position. If the oil pan was not
removed, lubricate the front of the oil pan seal with clean engine oil
to aid in reassembly.

Install the front cover to the engine. If the oil pan is still in
place, take care while engaging the front of the oil pan seal with the
bottom of the cover.

The 1996 4.3L engine covered by this guide uses a composite enginefront cover which must be discarded if it is removed from the engine.If a composite front cover is reused there is a good chance that itwill leak.

Disconnect the negative battery cable for safety.

Remove the water pump assembly from the engine. For details, please refer to the procedure found earlier in this section.

Remove the crankshaft pulley and damper. For details, please refer to the procedure found earlier in this section.

Loosen the oil pan to help provide clearance for front cover removal without damaging the front cover-to-oil pan seal.

Remove the crankshaft position sensor.

Remove the timing cover-to-engine bolts, then carefully removethe cover from the engine. Be careful not to damage the oilpan-to-front cover seal or sealing surfaces.

Discard the old timing cover.

Using a plastic scraper, solvent and a rag, clean the oil, grease and varnish from the mounting surfaces on the engine.

To install:

Lubricate the front of the oil pan seal with clean engine oil to aid in reassembly.

Install the new front cover to the engine, then tighten the front cover retaining bolts to 124 inch lbs. (14 Nm).

Tighten the timing cover bolts alternately and evenly, while gently pressing on the cover.

1996 ModelsThe 1996 4.3L engine covered by this guide uses a composite engine
front cover which must be discarded if it is removed from the engine.
If a composite front cover is reused there is a good chance that it
will leak.

Disconnect the negative battery cable for safety.

Remove the water pump assembly from the engine. For details, please refer to the procedure found earlier in this section.

Remove the crankshaft pulley and damper. For details, please refer to the procedure found earlier in this section.

Loosen the oil pan to help provide clearance for front cover removal without damaging the front cover-to-oil pan seal.

Remove the crankshaft position sensor.

Remove the timing cover-to-engine bolts, then carefully remove
the cover from the engine. Be careful not to damage the oil
pan-to-front cover seal or sealing surfaces.

Discard the old timing cover.

Using a plastic scraper, solvent and a rag, clean the oil, grease and varnish from the mounting surfaces on the engine.

To install:

Lubricate the front of the oil pan seal with clean engine oil to aid in reassembly.

Install the new front cover to the engine, then tighten the front cover retaining bolts to 124 inch lbs. (14 Nm).

Tighten the timing cover bolts alternately and evenly, while gently pressing on the cover.

.Once you have removed the engine front
cover , turn the engine to the marks as shown in the diagram.Lock the
crankshaft in this position with an old reverse light switch from the
gearbox by inserting it into the hole under the bell housing (manual
transmission).Before removing the belt , loosen 3 bolts on the injector
pump after you locked this with a 8.5 mm drill bit.Replace the belt and
pull the tensioner to 16 Nm.If you are fitting a whole pulley
replacement kit take note of the upgraded spacers and their position.Dont forget to tighten the injector pump bolts again after you tensioned the belt and recheck your timing marks..hope this helps

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Remove the connector bracket from the left cylinder head cover. Disconnect the right ignition coil connector, condenser connector and remove the bracket.

Remove the left cylinder head cover retaining bolts. Remove the cylinder head cover from the engine.

Remove the right cylinder head cover retaining bolts. Remove the cylinder head cover from the engine.

Set the No. 1 cylinder to TDC on the compression stroke. Turn the crankshaft pulley and align its groove with the timing mark T of the lower timing chain cover.

Check that the mark of the camshaft timing sprockets are in straight line positioning on the cylinder head surface. If not rotate the crankshaft 360 degrees. Do not rotate the engine counterclockwise.

Remove the oil pan. Remove the crankshaft damper pulley. Remove the timing chain cover.
NOTE
Be careful not to damage the contact surfaces of the cylinder block, cylinder head and timing chain cover. Before removing the timing chain, mark the right and left timing chains with an identification mark based on the location of the sprocket because the identification mark on the chain for TDC can be erased.

After compressing the timing chain tensioner, install a set pin. Remove the right cam to cam guide. Remove the right timing chain auto tensioner and timing chain tensioner arm.

Install the left timing chain. Be sure to install the chain with no slack between the camshaft and the crankshaft (crankshaft sprocket, timing chain guide, exhaust camshaft sprocket, intake camshaft sprocket). The timing mark of each sprocket should be matched with the timing mark (color ink) of the timing chain at installation of the timing chain.

Install the right timing chain. Be sure to install the chain with no slack between the camshaft and the crankshaft (crankshaft sprocket, intake camshaft sprocket, exhaust camshaft sprocket). The timing mark of each sprocket should be matched with the timing mark (color ink) of the timing chain at installation of the timing chain.

Pull out the pins on both the left and right hydraulic tensioners. Install the oil pump chain cover.

Rotate the crankshaft two revolutions in the clockwise direction. Confirm the timing mark. Be sure to rotate the crankshaft in the clockwise direction.

Apply sealant on the chain cover and on the cylinder head, cylinder block, and lower oil pan. Be sure these parts are free of engine oil and dirt.
NOTE
Before assembling the timing chain cover, the liquid sealant TB1217H should be applied on the gap between the cylinder head and block. The part must be assembled with five minutes after the sealant is applied.

Fig. Sealant application (1 inch bead width)-3.8L Engine

Apply sealant on the chain cover.
NOTE
The liquid sealant TB1217H should be applied on the gap between the cylinder head and block. The part must be assembled with five minutes after the sealant is applied.

Fig. Timing cover sealant application-3.8L Engine

Install a new gasket to the timing case cover.
NOTE
It is important that the dowel pins on the cylinder block and holes on the timing chain cover should be used as a reference in order to assemble the timing chain cover in the correct position.

Fig. Timing cover gasket installation (A) gaskets-3.8L Engine

Install the timing chain cover. Torque the retaining bolts in the proper sequence and to specification. The engine should not be started for at least thirty minutes after timing chain cover assembly.

Fig. Timing cover bolt torque sequence and specification-3.8L Engine

Install the timing case cover oil seal.

Continue the installation in the reverse order of the removal procedure.

Install a bolt in the end of the crankshaft
CAUTIONDo not install the crankshaft balancer bolt or a bolt longer than 1 inch or damage to the crankshaft threaded hole will result.

Rotate crankshaft until the number 1 piston is at Top Dead Center of compression stroke.

Make sure that the alignment marks are aligned with the tabs on the timing chain tensioner.

Measure distance between hole in bracket and unworn surface of timing chain tensioner shoe.
NOTE: If distance between the hole and unworn surface of timing chain tensioner is greater than 0.314 in (8 mm), replace tensioner, timing chain and sprockets.

Remove timing chain tensioner bolts.

Remove the timing chain, timing chain tensioner and camshaft sprocket at the same time.

Remove the crankshaft sprocket using special tool J 22888-20A or equivalent.

Remove crankshaft sprocket alignment key.

NOTE: If any camshaft components are being replaced to correct a noise problem, all camshaft drive components must be replaced.To Install:

Install the crankshaft sprocket alignment key.

Install the crankshaft sprocket using special tool J 5590 or equivalent.

Compress the timing chain tensioner spring and insert a pin into the tensioner hole to retain the tensioner shoe.

The jaguar v8 has 4 timing chains located on the front of the engine behind the aluminum timing cover.
You can inspect them by remove the valve covers but to replace them you need special factory tools to set the vehicle up on TDC.
The secondary timing chain tensioners are a common failure on this vehicle which will cause the chain to break.
You can replace the tensioners to prevent this failure just by removing the valve covers and exhaust sprocket, but if this is not the issue the chains should be lifetime, not like a timing belt which is required to be replaced by time and mileage.
JPTCAT